308 lines
9.5 KiB
Groff
308 lines
9.5 KiB
Groff
.\"-
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.\" Copyright (c) 2000, 2001, 2002 Robert N. M. Watson
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.\" All rights reserved.
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.\"
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.\" This software was developed by Robert Watson for the TrustedBSD Project.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd October 30, 2014
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.Dt ACL 3
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.Os
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.Sh NAME
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.Nm acl
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.Nd introduction to the POSIX.1e/NFSv4 ACL security API
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/types.h
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.In sys/acl.h
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.Sh DESCRIPTION
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.Fx
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permits file systems to export Access Control Lists via the VFS, and
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provides a library for userland access to and manipulation of these ACLs.
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.Fx
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supports POSIX.1e and NFSv4 ACLs, but
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not all file systems provide support for ACLs, and some may require that
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ACL support be explicitly enabled by the administrator.
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The library calls include routines to allocate, duplicate, retrieve, set,
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and validate ACLs associated with file objects.
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As well as the POSIX.1e routines, there are a number of non-portable
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extensions defined that allow for ACL semantics alternative to
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POSIX.1e, such as NFSv4.
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Where routines are non-standard, they are suffixed with _np to indicate that
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they are not portable.
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.Pp
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POSIX.1e describes a set of ACL manipulation routines to manage the
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contents of ACLs, as well as their relationships with files; almost
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all of these support routines are implemented in
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.Fx .
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.Pp
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Available functions, sorted by behavior, include:
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.Bl -tag -width indent
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.It Fn acl_add_flag_np
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This function is described in
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.Xr acl_add_flag_np 3 ,
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and may be used to add flags to a flagset.
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.It Fn acl_add_perm
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This function is described in
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.Xr acl_add_perm 3 ,
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and may be used to add permissions to a permission set.
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.It Fn acl_calc_mask
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This function is described in
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.Xr acl_calc_mask 3 ,
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and may be used to calculate and set the permissions associated with
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the
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.Dv ACL_MASK
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entry.
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.It Fn acl_clear_flags_np
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This function is described in
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.Xr acl_clear_flags_np 3 ,
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and may be used to clear all flags from a flagset.
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.It Fn acl_clear_perms
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This function is described in
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.Xr acl_clear_perms 3 ,
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and may be used to clear all permissions from a permission set.
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.It Fn acl_copy_entry
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This function is described in
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.Xr acl_copy_entry 3 ,
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and may be used to copy the contents of an ACL entry.
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.It Xo
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.Fn acl_create_entry ,
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.Fn acl_create_entry_np
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.Xc
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These functions are described in
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.Xr acl_create_entry 3 ,
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and may be used to create an empty entry in an ACL.
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.It Xo
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.Fn acl_delete_def_file ,
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.Fn acl_delete_def_link_np ,
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.Fn acl_delete_fd_np ,
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.Fn acl_delete_file_np ,
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.Fn acl_delete_link_np
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.Xc
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These functions are described in
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.Xr acl_delete 3 ,
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and may be used to delete ACLs from file system objects.
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.It Xo
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.Fn acl_delete_entry ,
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.Fn acl_delete_entry_np ,
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.Xc
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This functions are described in
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.Xr acl_delete_entry 3 ,
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and may be used to delete an entry from an ACL.
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.It Fn acl_delete_flag_np
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This function is described in
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.Xr acl_delete_flag_np 3 ,
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and may be used to delete flags from a flagset.
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.It Fn acl_delete_perm
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This function is described in
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.Xr acl_delete_perm 3 ,
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and may be used to delete permissions from a permset.
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.It Fn acl_dup
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This function is described in
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.Xr acl_dup 3 ,
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and may be used to duplicate an ACL structure.
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.It Fn acl_free
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This function is described in
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.Xr acl_free 3 ,
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and may be used to free userland working ACL storage.
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.It Fn acl_from_text
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This function is described in
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.Xr acl_from_text 3 ,
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and may be used to convert a text-form ACL into working ACL state, if
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the ACL has POSIX.1e or NFSv4 semantics.
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.It Fn acl_get_brand_np
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This function is described in
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.Xr acl_get_brand_np 3
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and may be used to determine whether the ACL has POSIX.1e or NFSv4 semantics.
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.It Fn acl_get_entry
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This function is described in
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.Xr acl_get_entry 3 ,
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and may be used to retrieve a designated ACL entry from an ACL.
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.It Xo
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.Fn acl_get_fd ,
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.Fn acl_get_fd_np ,
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.Fn acl_get_file ,
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.Fn acl_get_link_np
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.Xc
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These functions are described in
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.Xr acl_get 3 ,
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and may be used to retrieve ACLs from file system objects.
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.It Fn acl_get_entry_type_np
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This function is described in
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.Xr acl_get_entry_type_np 3 ,
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and may be used to retrieve an ACL type from an ACL entry.
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.It Fn acl_get_flagset_np
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This function is described in
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.Xr acl_get_flagset_np 3 ,
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and may be used to retrieve a flagset from an ACL entry.
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.It Fn acl_get_permset
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This function is described in
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.Xr acl_get_permset 3 ,
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and may be used to retrieve a permset from an ACL entry.
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.It Fn acl_get_qualifier
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This function is described in
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.Xr acl_get_qualifier 3 ,
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and may be used to retrieve the qualifier from an ACL entry.
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.It Fn acl_get_tag_type
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This function is described in
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.Xr acl_get_tag_type 3 ,
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and may be used to retrieve the tag type from an ACL entry.
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.It Fn acl_init
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This function is described in
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.Xr acl_init 3 ,
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and may be used to allocate a fresh (empty) ACL structure.
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.It Fn acl_is_trivial_np
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This function is described in
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.Xr acl_is_trivial_np 3 ,
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and may be used to find out whether ACL is trivial.
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.It Xo
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.Fn acl_set_fd ,
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.Fn acl_set_fd_np ,
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.Fn acl_set_file ,
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.Fn acl_set_link_np
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.Xc
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These functions are described in
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.Xr acl_set 3 ,
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and may be used to assign an ACL to a file system object.
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.It Fn acl_set_entry_type_np
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This function is described in
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.Xr acl_set_entry_type_np 3 ,
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and may be used to set the ACL type of an ACL entry.
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.It Fn acl_set_flagset_np
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This function is described in
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.Xr acl_set_flagset_np 3 ,
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and may be used to set the flags of an ACL entry from a flagset.
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.It Fn acl_set_permset
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This function is described in
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.Xr acl_set_permset 3 ,
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and may be used to set the permissions of an ACL entry from a permset.
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.It Fn acl_set_qualifier
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This function is described in
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.Xr acl_set_qualifier 3 ,
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and may be used to set the qualifier of an ACL.
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.It Fn acl_set_tag_type
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This function is described in
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.Xr acl_set_tag_type 3 ,
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and may be used to set the tag type of an ACL.
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.It Fn acl_strip_np
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This function is described in
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.Xr acl_strip_np 3 ,
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and may be used to remove extended entries from an ACL.
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.It Xo
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.Fn acl_to_text ,
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.Fn acl_to_text_np
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.Xc
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These functions are described in
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.Xr acl_to_text 3 ,
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and may be used to generate a text-form of a POSIX.1e or NFSv4 semantics ACL.
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.It Xo
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.Fn acl_valid ,
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.Fn acl_valid_fd_np ,
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.Fn acl_valid_file_np ,
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.Fn acl_valid_link_np
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.Xc
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These functions are described in
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.Xr acl_valid 3 ,
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and may be used to validate an ACL as correct POSIX.1e-semantics, or
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as appropriate for a particular file system object regardless of semantics.
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.El
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.Pp
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Documentation of the internal kernel interfaces backing these calls may
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be found in
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.Xr acl 9 .
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The syscalls between the internal interfaces and the public library
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routines may change over time, and as such are not documented.
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They are not intended to be called directly without going through the
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library.
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.Sh SEE ALSO
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.Xr getfacl 1 ,
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.Xr setfacl 1 ,
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.Xr acl_add_flag_np 3 ,
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.Xr acl_add_perm 3 ,
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.Xr acl_calc_mask 3 ,
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.Xr acl_clear_flags_np 3 ,
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.Xr acl_clear_perms 3 ,
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.Xr acl_copy_entry 3 ,
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.Xr acl_create_entry 3 ,
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.Xr acl_delete_entry 3 ,
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.Xr acl_delete_flag_np 3 ,
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.Xr acl_delete_perm 3 ,
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.Xr acl_dup 3 ,
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.Xr acl_free 3 ,
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.Xr acl_from_text 3 ,
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.Xr acl_get 3 ,
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.Xr acl_get_brand_np 3 ,
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.Xr acl_get_entry_type_np 3 ,
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.Xr acl_get_flagset_np 3 ,
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.Xr acl_get_permset 3 ,
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.Xr acl_get_qualifier 3 ,
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.Xr acl_get_tag_type 3 ,
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.Xr acl_init 3 ,
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.Xr acl_is_trivial_np 3 ,
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.Xr acl_set 3 ,
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.Xr acl_set_entry_type_np 3 ,
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.Xr acl_set_flagset_np 3 ,
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.Xr acl_set_permset 3 ,
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.Xr acl_set_qualifier 3 ,
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.Xr acl_set_tag_type 3 ,
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.Xr acl_strip_np 3 ,
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.Xr acl_to_text 3 ,
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.Xr acl_valid 3 ,
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.Xr posix1e 3 ,
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.Xr acl 9
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.Sh STANDARDS
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POSIX.1e assigns security labels to all objects, extending the security
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functionality described in POSIX.1.
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These additional labels provide fine-grained discretionary access control,
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fine-grained capabilities, and labels necessary for mandatory access
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control.
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POSIX.2c describes a set of userland utilities for manipulating these
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labels.
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.Pp
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POSIX.1e is described in IEEE POSIX.1e draft 17.
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Discussion of the draft continues on the cross-platform POSIX.1e
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implementation mailing list.
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To join this list, see the
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.Fx
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POSIX.1e implementation page for more information.
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.Sh HISTORY
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POSIX.1e support was introduced in
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.Fx 4.0 ;
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.Fx 5.0
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was the first version to include a complete ACL implementation based
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on extended attributes for the UFS and UFS2 file systems.
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NFSv4 ACL support was introduced in
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.Fx 8.0 .
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.Pp
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The
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.Xr getfacl 1
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and
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.Xr setfacl 1
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utilities describe the user tools that permit direct manipulation of complete
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file ACLs.
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.Sh AUTHORS
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.An Robert N M Watson
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